<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>use strict</title>
</head>

<body>
  <script>


    // "use strict";
    // var x = 10;
    // console.log(x);

    // y = 5;
    // console.log(y);

    "use strict"
    // console.log(delete x);
    console.log(delete globalThis.x);
  </script>
</body>

</html>